j0ekerr: I would contest your statement by saying that it's a legitimate marketing strategy to get gamers to buy the sequel.
Stilton: You're probably right, but the amount of times it was free or going cheap smacks a bit of desperation. Maybe its all a part of a Runic Games master plan....
Some desperation or necessity might well play into it. I hear that torchlight 2 was significantly more expensive than the first. Thus the need for a quick cash grab by making people interested in the franchise with a free game then turning them into paying customers with Torchlight 2. Yes they lose profit from the freebie but that game has already run its course and paid for itself.
It sounds convoluted but in the dark land of Mord... I mean accounting, stuff often is.